1. Field of the Invention
This invention relates to data storage and, more particularly, to techniques for performing write logging when accessing a data volume shared between multiple hosts.
2. Description of the Related Art
Many business organizations and governmental entities rely upon applications that access large amounts of data, often exceeding a terabyte or more of data, for mission-critical applications. Many of these applications require near-continuous access to data. For example, many systems such as retail processing databases, airline reservation databases, and financial institution databases must be available to perform transaction processing 24 hours a day. Downtime associated with such systems can be disastrous.
With the growing amounts of data and shrinking acceptable downtime requirements of modern systems, organizations are sometimes forced to choose between the conflicting demands associated with modern systems. For example, secondary operations such as data backup operations, reporting and analysis, and application testing can be of significant importance. However, such secondary operations can interrupt or encumber the normal transaction processing of a host system running various applications. For example, various storage techniques such as copy-on-write snapshots, replication, and RAID (Redundant Array of Independent Disks) processing may be implemented to increase reliability and/or availability of a storage volume. However, the complex operations used to implement block storage features such as these may undesirably add to the latency of block operations to the underlying storage volume.